Climate change deniers who patrol the second defensive line, the moat, agree that the planet is warming but they dispute that the cause is human greenhouse gas emissions (GHGs). They say that there is not enough evidence to support this view and governments should not act until there is more evidence. This is just a delay tactic, and fortunately it has been ignored by nearly every government on the planet many of which have spent the past two decades enacting policies and plans that have started their transition to low-carbon economies. Examples of recent action are shown on the Transformation tab above.
Richard Muller is the latest scientist to support the view that human generated GHGs are the main forcing element behind the current warming. He argues, as many others have, that when you compare the few vaguely plausible explanations for changing climate - greenhouse forcing, solar forcing, aerosol forcing, big changes in albedo - one fits the data MUCH better than any of the others. That one is greenhouse gases.
It's like a race between the contenders, and GHG has lapped the field twice to come in well ahead of the pack. This is not enough for some people, they want GHGs to win the race at the speed of light before they'll accept the evidence.
Paul Fisher put it like this:
If a house is burning down and I suggest a bucket brigade, slow and cumbersome as it might be, there is no value in pointing out the chances of it working are slim unless you have something better to use in replacement. Simply allowing the house to burn down is not a useful solution. It is, at least, time to stop pretending the house isn't full of bad wiring that should be replaced, even if we can't agree there are already sparks and the walls are smoking.